Counterbalancing means



Aug. 19, 1952 J, H; MCKEE 2,607,410

COUNTERBALANCING MEANS Filed Jan. 12, 1949 5 Sheets-Sheet 1 19, 1952 J. H. M KEE CQUNTERBALANCING MEANS 7 3 Sheets-Sheet 5 Filed Jan. 12, 1949 6 /Z a) CZZarhe Patented Aug. 19, 1952 COUNTERBALANCING MEANS James H. McKee, Aurora, 111., assignor to McKee Door Company, Aurora, 111., a corporationof Illinois 7 Application January 12, 1949, Serial No. 70,543 f (or. 1e0191) 3 Claims. 1

' My invention relates to counterbalancing means and is more particularly concerned with counterbalancing means for overhead types of doors commonly used in garages, servicestations and other buildings.

The conventional overhead type of door consists of a multisection door provided with rollers at its edges'for engaging guiding and supporting tracks located on opposite sides of the door opening and having horizontal and vertical portions connected by curved portions whereby the door may be moved from a vertical closed posi- 'tion to a horizontal open position, and vice versa.

Such a door is ordinarily counterbalanced by providing a tension spring or torsion spring and drum above the door opening and at either side thereof, each tension spring or drum being con- ;nected by the cable to a fitting at the bottom of the door adjacent one edge thereof.

' In some instances a single torsion spring is attached to a shaft extending transversely of the door opening and having a drum at either end thereof for receiving one of the cables attached to the lower edge of the door. It is also known to provide counterbalancing weights in lieu of the springs located at either side of the door. All of these prior art constructions are objectionable from the standpoint of cost and some at least are objectionable on the ground that they occupy space which could be otherwise used or which is not available in certain types of buildings.

An object of my invention is to provide anew and improved counterbalancing means which overcomes these objections of the prior art.

Another object of my invention is t provide a new and improved counterbalancing means which utilizes only a single spring but which does not require the shaft and double drum construction of the prior'art.

Another object of my invention is to provide new and improved counterbalancing means which is cheaper and easier to manufacture and install than the prior art constructions.

Another object of my invention is to provide acounterbalancing means having a unique arrangement of guiding sheaves and cables.

Another object of my invention is to provide a new and improved guiding sheave.

' Other objects and advantages will become apparent as the description proceeds.

In the drawings:

Fig. 1 is a perspective rear view of an overhead type of door embodying one form of my invenj'tion; 1

Fig. 2 is an enlarged view showing the unique arrangement of cables and sheaves utilized in the construction of Fig. l;

Fig. 3 is a view similar to Fig. 2 but showing a variation in the cabl arrangement;

Fig. 4 is a perspective rear view of the upper part of a door construction embodying a third form of my invention; and

Fig. 5 is a view similar to Fig. 4 but showing a construction embodying a fourth form of my invention.

Referring particularly to Fig. 1, it will be noted that I have therein illustrated an overhead type.

of door construction including a door indicated generally by reference character 10 and composed of sections 12, 14,16, and 18 connected by suitable hinges 20. Opposite sides of the door are provided with the usualrollers engaging the tracks 22 located on opposite sides of the door opening and affixed in the usual manner to the doorjambs' and ceiling or roof of the building.

The tracks have vertical portions 24 and horizontal portions 26 connected by curvedportions 28. The door I0 is provided with the usual handle 30 and pull-down rope 32 for moving the door between the closed position shown and an open position in which the door-rests. in the horizontal portions of the tracks 22 and for moving the door back to closed'position. V

A single torsion spring '34 is mounted above the door opening adjacent the rear end of the horizontal portion of'one track. This spring is mounted on a rod supported at one end in a bracket 36 attached to the ceilingor roof of the building, the other end of therod being mounted in an auxiliary bracket 3'1 attached to a main bracket 38 also serving as a support for the rear end of the left-hand track, as viewed in Fig. 1. The torsion spring 34 is connected to a single drum 40. One end. of a rope or form-of cable or pull line 42 is attached to the drum 40, the other end of this cable being bent around a metal eyelet 44 and secured by clamps 46, as best shown in Fig. 2. The eyelet 44 passes loosely through a second metal eyelet or sheave device 48. The eyelet 48 is'located in a reverse bend of a second cable 50.

One leg 52 of the cable 50 passes over a sheave 54 and extends downwardly along the left side of the door and is fastened by any suitable means adjacent the lower left-hand corner thereof. A second leg '56 of the cable 50 passes around a sheave 58 and then transversely above the door opening to a second sheave 60 located above the- 3 cable then passes downwardly along the righthand edge of the door and is attached thereto adjacent the lower right-hand corner.

The sheaves 54 and 58 are rotatably mounted on studs 62 and 64, respectively, provided by a bracket 66 which is L-shaped and attached in any suitable manner to the building structure above the left-hand edge of the door opening. The sheave 60 is rotatably mounted on a pin 68 carried by a yoke 70. The yoke is pivotally mounted in a bracket 12 for movement in a plane perpendicular to the plane of the sheave 60.

In the embodiment shown in Figs. 1 and 2, the door may be raised by pulling upwardly on the handle or rope 32 or by pulling upwardly on any suitable handle means (not shown) provided on the outside of the door. As the door moves upwardly and rearwardly in its tracks,

the cable 42 is wound on the drum and the torsion spring exerts a counterbalancing force which is appliedrto the lower corners of the door through this cable 42 and cable 50. This latter cable can slip with respect to its eyelet 48 automatically toadjust any inequalities in the pull exerted on the legs 52am; 56 of this cable. The construction and arrangement of the parts is such that the door reaches its uppermost posi- .tion before the clamps 46 have moved far enough to engage thedrum 40, so that this drum need only be of such size as to accommodate the single I cable 42.

As the door approaches its'uppermost position,

' the rollers attached to the opposite sides of the I lower edge of the door enter the curved portions of the tracks, thereby moving this lower edge rearwardly or away from the door opening. The pivotal mounting of the sheave 60 is designed to accommodate this rearward movement 'of the lower edge of the door to which the end of leg 56 of the cable is attached. As, the lower edge of the door moves rearwardly, the sheave swings about its pivotto assume a rearwardly and downwardly inclined position so that there is no tendency to pull the cable ofi" of the sheave 68. When the door is lowered, the sheave returns to a substantially vertical position.v

While the slipping of the cable 50 about its eyelet 48 is desirable where'the door is perfectly balanced,-,such slippage'is to be avoided where the door is of: such construction that it is in- 'herently unbalanced; that is, where'one sideof the door is heavierthan the other. With such an unbalanced door, the cable arrangement of Fig. 3 is preferable. This cable arrangement is identical with that of Fig. 2 except'that clamps 14 are attached to the cable 50 immediately adjacent its eyelet 48 to preventany shortening or lengthening of the cable leg 52 with respect to the cab-le leg 56.

The construction shown in Fig. 4 is generally similar to the constructions of Figs. 1, 2,, and 3 54' and thence to drum 82 to which its other end is attached. This construction most nearly redesigned to receive two cables I06 and I 08.

sembles the construction of Fig 3 in that both cables are rigidly attached to the drum 8'2 and Each of the cables I05 and I08 has an end attached to the doorjamb, as indicated at H0. The cable I65 engages sheave 58" and thence extends transversely above the door opening to the pivot sheave as" and thence downwardly along the left-hand side of the door, and is attached to the lower left-hand corner. The cable I08 passes over a fixed sheave 54" and downwardly along the right -hand edge of the door, and has its'lower end 'aifix'ed to the lower righthand corner thereof.

When the door in the embodiment of Fig. 5 is moved upwardly, the spring-I00 contracts and pulls the sheave I64 toward the fixed slippqrt I62, thereby forming larger'loops in the cables I96 and I08 and exerting a decreasing pull oh these cables Comparable 'with'the decrease in weight ofthe portion or the door-remaining i'n thevertical portions of. the tracks. As the door is subsequently lowered, th'e'spring I59 stretches to the length shown, and the loops in the cables me and ma ecome progressivew smaller. It will be noted that in this embodiment no drum is required. 7

From the foregoing description taken in connection with the accompanying drawings, it will be apparent that I have provided new, simplified,

and less expensive means for counterbalancing a multisection door movable between a closed vertical position and an open horizontal-position. While I have shown ohly a few embodiments of my invention, it is to be understood thatmy invention may assume numerous forms and includes all variations, modifications, and equivalents coming within the appendedcl'aims.

Iclaim:

lgcounterbalancing mechanism for an overhead door movable upwardly and rearwardlyffrom a vertical closed position across a door opening to "an overhead horizontal open position, and having guide rollers carried on the sides of the door and en-gageable with side guideways for guiding movement of. the door, said'mechanism comprising a continuous cable having its ends connected to the lower oppositesides oflthe door, means for exerting a rearward pull on; an intermediate looped portion of the oable to raise the door, said means including. a; pull line extending horizontally and rearw'ardly adjacent one side of the doorwhen it is inraised position, tension means exerting a continuous rearward pullon, said pull line at least until said docr is substantially in raised position, a sheave device carried at the forward end of the pull line about which said intermediate portionorthe cab leis looped for adjusting movement thereon, and cable guiding means for guiding the cable during door movement, said cable guiding means including vertically and horizontally pivoted .s heaves located above the door opening in substantial alignment with saidpull line, b'otli. sheaves, having their pivots normal to the direction of movement of the pull line, and a third sheave located above the door opening at the other side edge of the door. said third sheave having its pivot substantially parallel to the pull line when the door is closed, whereby the sheave is in a vertical plane, and a pivoted bracket mounting said third sheave, the pivot for said bracket being horizontal and parallel to the plane of the door opening, whereby said third sheave may swing into a. horizontal plane when the door is in raised position.

2. Counterbalancing mechanism for an overhead door movable upwardly and rearwardly from a vertical closed position across a door opening to an overhead horizontal open position, and having guide rollers carried on the sides of the door and engageable with side guideways for guiding movement of the door, said mechanism comprising a continuous cable having its ends connected to the lower opposite sides of the door,

means for exerting a rearward pull on an intermediate looped portion of the cable to raise the door, said means including a pull line extending horizontally and rearwardly adjacent one side of the door when it is in raised position, tension means exerting a continuous rearward pull on said pull line at least until said door is substantially in raised position, a sheave device carried at the forward end of the pull line about which said intermediate portion of the cable is looped, and cable guiding means for guiding the cable during door movement, said cable guiding means including vertically and horizontally pivoted sheaves located above the door opening in substantial alignment with said pull line, both sheaves having their pivots normal to the direction of movement of the pull line, and a third sheave located above the door opening at the other side edge of the door, said third sheave having its pivot substantially parallel to the pull line when the door is closed, whereby the sheave is in a vertical plane, and a pivoted bracket mounting said third sheave, the pivot for said bracket being horizontal and parallel to the plane of the door opening, whereby said third sheave may swing into a horizontal plane when the door is in raised position.

"3. The counterbalaneing mechanism as set forth in claim 1 in which the vertically and horizontally pivoted sheaves are mounted on a right-angle bracket for ready attachment over the door opening.

JAMES H. McKEE.

REFERENCES CITED ihe following references are of record in the I file of this patent:

UNITED STATES PATENTS Allison June 21, 1949 

